In the manufacture of a device such as a semiconductor device or the like, a process of filling silicon into a depression such as a through-hole or a contact hole formed on an insulating film is performed. The silicon filled into the depression can be used as, e.g., an electrode.
In a process of the related art, a polycrystalline silicon film is formed on a wall surface of a workpiece, which defines a trench. Subsequently, an amorphous silicon film is formed on the polycrystalline silicon film. Thereafter, the workpiece is annealed. In this process, by annealing the workpiece, amorphous silicon is moved toward the bottom portion of the trench, whereby the trench is filled with the amorphous silicon.
However, in the process mentioned above, when the amorphous silicon is moved toward the bottom portion of the trench by annealing, the amorphous silicon agglomerates. As a result, cavities called voids or seams are formed.
Under these conditions, there is a need to suppress the generation of cavities when filling a depression.